Say what you will about them being rapey as all getout, in this case it's practically justified (this being a monster that normally does have a reputation for large amounts of murder, when the setting does its best to refluff peril into porn it's something of a foregone conclusion).
That said, the 'lust build-up turns their mana red' idea is an interesting way to spin the classic trait, in my opinion.
. . . is it wrong that the penultimate paragraph is leading me to look forward to seeing some fluffy-cuddly fanart of her?